I don't think anyone has stated the obvious yet.... A lot of the reason theism is so proudly trumpeted and atheism is not, is that theism generally comes with a desire to "save the souls" of others (quite a pressing goal), emotional entanglement(j-man loves me, i love j-man kinda thing), and a lot of "righteous" zealotry. When theism meets atheism, theism tends to be pushier by nature.... We are not trying to keep anyone from hell or trying to impose our moral system on anyone, few atheists do anyway. It's sort of like comparing the car sales of a car salesman with that of a non-car salesman, one is just more invested.
The worst part is that all of society's ideals are based on a common religion, at least in the United States. Even minute things, like the work day and approaches to education, always have a Christian undertone here. Oh well, that is why the entire system has to come down.